Activities conducted within the context of this project include: 1. Trace and update contact information for BLSA participants who discontinued but did not formally withdraw study participation who were last contacted (in person or over the telephone) at least once since 1990. 2. Make a telephone contact with eligible BLSA participants to establish current status and williness to attend a BLSA clinic visit, participate in the home visit program or complete a telephone interview. 3. Create a formal process for tracking, contacting and following BLSA participants, and implement a process in which in-clinic and home visits are integrated and serve complementary purposes. 4. In BLSA participants enrolled in the home visit program, conduct an extensive assessment of health status, aimed at ascertaining multiple health-related outcomes (dementia, mobility limitation, ADL disability, frailty, CHD, cancer, etc.). 5. In BLSA participants enrolled in the home visit program, collect a blood sample to be used for basic tests of clinical chemistry, DNA extraction and storage of cells, serum and plasma. 6. Provide participants and their families with a detailed description of the study, and obtain informed consent for participation, including consent for the use of previously collected biological specimens. 7. Create a database with tracking information and all information collected over the telephone interview and during in person home visits, maintaining full compatibility with the BLSA core database.